Highway construction to the reinforced earth retaining wall which is under constant traffic load there is a possibility of generating the displacement at the top. In this study, it was conducted determine how to repair reinforcement method through examination of cause and stability analysis when occurs the displacement of reinforced earth retaining wall.

This paper is developed the viscoelastic dumpers whose multilayer system absorbs weight transmitted to framed structure sliding down along specific layer elements. Experiments with and without viscoelastic dumpers were carried out. According to the results, I could confirm that interstory drift ratio of steel frame structure has effectively decreased on both 1st and 2nd floor compared to that of before.

We have tested the measuring system that can monitor the dynamic behaviour of floating structure by various sensors. In this paper, we present a initial result using a low-cost GPS sensor, which showed the inaccurate position and insufficient frequency for a floating structure.

지진으로 유발되는 산사태의 잠재적 피해를 줄이기 위해 산사태 재해도에 관한 연구가 활발하게 진행되고 있다. 산사면의 경우, 대상 지역이 광범위하므로 동적해석을 평가하는 것이 불가하며 한계평형법이나 사면에 발생하는 영구변위로써 산사태 재해를 예측한다. 기존에 수행된 다양한 사례연구로부터 한계평형법에 기초한 안전율을 통한 평가방법의 부정확함은 입증되었으며 산사태 위험도는 영구변위를 이용하여 평가된다. 미국에서는 산사태 위험도를 영구변위에 따라서 4개의 등급으로 분류한다. 본 연구에서는 수정된 Newmark 변위법으로 산사태 위험도 등급을 평가하였으며 예측된 등급을 2차원 동적해석으로 수행된 해석 결과와 비교하여 정확도를 평가하였다. 비교 결과, 산사면의 증폭 특성을 고려하며 지진파의 최대지반가속도, 최대지반속도, Arias 진도, 평균주기를 고려할 경우, 예측된 위험도 등급의 신뢰도가 높은 것으로 나타났다. 반면, 산사면의 증폭특성을 고려하지 않을 경우, 지진으로 유발된 진동을 과대예측하는 것으로 나타났다.

본 연구에서는 카메라의 위치에 상관없이 정확하게 구조물의 변위를 측정할 수 있는 영상 기반 변위 계측 시스템을 제안하였다. 기존의 영상 기반 변위 계측 시스템은 카메라의 각도에 따라 오차를 유발하며, 그에 따라 대형 구조물에서 적용성에 제한되는 단점이 존재하였다.본 시스템은 네 개의 점이 그려진 측정판을 변위를 측정하고자 하는 구조물의 위치에 부착하여 카메라로 촬영한 뒤 영상을 해석하여 변위를 얻는다. 측정판과 카메라의 각도에 무관하게 구조물의 변위를 얻기 위하여, 이미지 좌표계와 세계 좌표계 상의 두 평면간의 대응관계를 표현하는 평면 호모그래피 기법을 활용하였다. 성능 검증을 위하여 소형 구조물을 이용한 실내실험을 수행하였으며, 어떠한 각도에서 촬영하더라도 실제 변위를 정확하게 측정할 수 있음을 보였다.

SHM에서 변위는 구조물의 동적 특성을 파악하는 핵심정보다. 이를 구조물과 직접 접촉하여 자기장 변화를 전기적신호(LVDT), 직접적으로 측정하는 방안으로 LVDT, GPS, LDV Displacement is one of the most fundamental responses, containing useful information regarding dynamic behavior of a structure. Traditional displacement measurement devices such as LVDT have disadvantages in its high-cost and few options on installation place. For the sake of economic reason, vision-based displacement measurement systems using low-cost cameras have been developed, yet these approaches still have difficulties in finding appropriate camera positions; camera should be placed perpendicular to targets. This study presents a new vision-based displacement measurement system using the planar homography method that gives accurate displacement, allowing the camera to have an arbitrary angle toward target. The vision-based system is experimentally verified using a low-cost camera and a target with four circles.

The purpose of this study is model development of displacement estimation of simple beam receiving the concentrated load using terrestrial LiDAR. Using the terrestrial LiDAR it is possible to supplement touch sensor’s disadvantages which have the limit to the displacement measurement. The data which is obtained by terrestrial LiDAR goes through coordinate transformation and dividing elements. And then, applying the Cubic Smoothing Spline Interpolation(CSSI) we will find the optimal value for displacement estimation. Also, based on the assumed displacement it is possible to estimate the stress distribution shape of the experiment model.

A dynamic displacement estimation system is developed by integrating laser Doppler vibromter (LDV) and light detection and ranging (LiDAR). The system includes hardware level integration for simultaneous measurement of two devices and data fusion of two measurement signals based on Kalman filter smoothing algorithms. For hardware integration of two devices, the laser beam directions and the triggering of measurement of LDV and LiDAR are controlled on the level of built-in commands of the devices. The distance data sequentially measured by LiDAR is converted to dynamic displacement of high noise and low sampling rate, and fused with the velocity measured by LDV which has high sampling rate and low noise but accumulated bias error when integrated. Using the Kalman filter based data fusion algorithm, it is able to estimate dynamic displacement in which the drawbacks of two devices are effectively removed. The proposed system is applied to a dynamic loading test on a highway bridge and the performance is verified.

Displacement is one of the most fundamental responses, containing useful information regarding dynamic behavior of a structure. Traditional displacement measurement devices such as LVDT have disadvantages in their high cost and few options on installation locations. For the sake of economic reason, vision-based displacement measurement systems using low cost cameras have been developed, yet these systems still have difficulties in finding appropriate camera positions; camera should be placed perpendicular to targets. This study presents a new vision-based displacement measurement system using the planar homography method that results in accurate displacement measurement, allowing the camera to face targets with an arbitrary angles. The proposed vision-based system was experimentally validated from a laboratory test.

In order to measure the real-time displacement of a rail with train vehicles on service, a displacement meter has to be installed near the rail in conventional method. However, on this study, an innovative method is developed to measure the displacement of rail in real-time using laser vibrometer in a distance.

구조물은 시공 단계에서의 작업환경과 시공품질 그리고 자연환경과 불확실한 하중 등 수많은 변수들에 의해 해석 모델과 큰 차이를 보인다. 따라서, 구조물에 센서들을 설치하여 계측된 값으로 Structural Health Monitoring (SHM)을 실시하여 구조물의 안전성을 진단하고 있다. 하지만 대형화, 비정형화 되어가고 있는 건축 구조물에서 부분적으로 계측한 데이터로 전체 안전성에 대한 평가는 현실적으로 힘든 상황이다. 정확한 구조물 평가를 위해서는 보다 많은 센서의 개수가 필요하며, 장기간의 계측 기간이 요구된다. 그러나 재정적 문제 및 현장 여건 등으로 인해 설치되는 센서의 수 및 계측 기간은 제한이 될 수밖에 없다. 따라서 요구되는 구조물 진단의 정확성을 확보하면서 소요되는 비용을 최소화할 필요가 있다. 이를 위해서는 먼저 구조물 진단의 정확성과 비용과의 관계를 파악할 필요가 있다. 본 연구에서는 부분적으로 계측한 변위 값을 이용하여 구조물 전체의 변위를 예측하는 알고리즘을 제시하고, 계측 기간에 따른 알고리즘의 정확도를 평가한다. 이를 통해 요구되는 신뢰도를 가지면서 최소의 계측 기간을 파악할 수 있다. 이는 유지관리 비용을 절감하는 비용효과를 가진다.

The local displacement in the downstream of the embankment dam has been observed since the 2nd precise inspection was investigated. It appears that this displacement is caused by the differential settlement on the different properties of the zone during the construction. Therefore, using the advanced inspection method of the 3D scanning determines whether to proceed with the displacement. In this study, reviewing a field application and analyzing results of the 3D scanning method are drowned a conclusion for improvement in the inspection and maintenance method on the Rock-fill type embankment dam.

Displacement is one of the most fundamental responses, containing useful information regarding dynamic behavior of a structure. Traditional displacement measurement devices such as LVDT have difficulties in using for full-scale civil structures mainly due to the installation inconvenience. The use of laser-based measurements is rapidly increasing; however, the high equipment cost prevents its wider adoption. This study uses a vision-based displacement measurement system as a cost-effective and practical solution for field testing. The vision-based system is used to measure vertical deflections of a railway bridge for high-speed trains to validate its applicability for the bridge deflection measurement.

In this study, a new damage detection method using an inclinometer which can directly measure rotational displacement is developed and its effectiveness investigated. In order to verify the attractive features of the proposed method such as an increase in sensitivity and the data loss minimization, numerical analyses were performed by the uniform load surface curvature (ULSC) method, which is the damage detection method based on the modal flexibility matrix. For numerical analysis, 2 m simply supported beam, which has 20 elements and 21 nodes is considered. From the results of the eigenvalue analysis, the damage locations were perfectly detected in each damage case. It shows that the damage detection using rotational displacement is theoretically possible. From the result of numerical simulations, the damage locations were detected exactly. When compared with the detection method based on vertical displacements obtained from accelerometers, it is shown that using the rotational displacement is much more sensitive than using the vertical displacement. Overall, when compared with the accelerometer data, the damage detection performed by an inclinometer was more sensitive.

In this study, bearing capacities under large lateral displacement were obtained using the formulas suggested by Naeim & Kelly(1999) and ISO 22762 Part.3(2010) and those were compared with the results of Hwang's experiments(2006) to decide which formula is more reasonable

The sensors currently installed for bridge monitoring are faced with limitations in terms of the application and effectiveness of such systems in current long sized bridges, which are developing rapidly in terms of both size and function. Global Navigation Satellite System (GNSS) has been noted as an only way to overcome the limitations of such sensors. This is because they have numerous desirable characteristics that outweigh their high cost. However, GNSS installed for bridge monitoring has been used so far only in measurement of bridge displacement. Therefore, in this study, verify the usability of GNSS through correlation analysis between deflection and temperature